In order to accommodate the development of integrated circuits, a larger number of elements have to be held in a limited area of a PCB, thus imposing more stringent requirements on the spacing, the size, etc., of the elements on the PCB.
A Ball Grid Array (BGA), which may be included in a PCB and is structured as an array of ball grids, is a method of packaging an integrated circuit using an organic carrier board and has the characteristics of (1) a reduced packaging area, (2) more functions and a larger number of pins, (3) the PCB capable of being self-aligned and easily tin-plated during welding; (4) high reliability; (5) good electrical performance and overall low cost, etc.
In order to use space more effectively and improve the performance of a product, a line can be designed to travel between pads (BGA pads). One or more lines can be designed to travel between two pads in order to provide better performance. Integrated elements become increasingly smaller and have an increasing number of functions. As a result, for each integrated element: the number of pads increase; the pad area becomes smaller for each pad; and the spacing between pads becomes narrower. In order to satisfy design requirements, a line often has to be arranged between two pads, thus making the spacing between the line and the pad smaller, and the line width smaller.
The inventors have identified during making of a technical solution in embodiments of the invention at least the following technical problems in the prior art:
When the required distance between the line and the pad is too small to satisfy a required spacing necessary for fabrication, it may be impossible or difficult to fabricate a PCB, or a PCB may be fabricated at a low yield rate.